Merck Hits 55% NSCLC ORR With MK-2010, Won't Commit to Phase 3

Merck’s MK-2010 posted a 55% unconfirmed overall response rate among 11 previously untreated PD-L1-positive non-small cell lung cancer patients, the first clinical data from the PD-1xVEGF bispecific since Merck licensed it from LaNova Medicines 16 months ago.

The number sits close to ivonescimab’s 50% ORR from the Harmoni-2 China phase 3 trial in a comparable first-line NSCLC setting. BioNTech and Bristol Myers Squibb’s pumitamig came in at 47%. Pfizer’s PF-08634404 hit 62% and 55% at its two dose levels. The difference: all three competitors have pivotal trials running. Merck doesn’t.

The data, presented as a poster at AACR from a Chinese phase 1/2 trial, covered 72 patients across NSCLC backfill cohorts. At 30 mg/kg, ORR dropped to 44% among nine patients. Grade 3-plus treatment-emergent adverse events landed at 23% in the 20 mg/kg cohort versus 49% at 30 mg/kg, with the maximum tolerated dose still not established.

Merck won’t say when phase 3 begins. A spokesperson cited early-stage development, adding that MK-2010 would be evaluated as monotherapy and in combination settings. Meanwhile, Merck is running a 17-trial phase 3 program for TROP2 ADC sac-TMT, and Summit already submitted ivonescimab for FDA approval in EGFR-mutated NSCLC.

Leerink Partners wrote on March 18 that Merck “could quickly catch up to competitors in the class, if they so choose to do so.”

Data cutoff was Dec. 25, 2025.

— Sarah Chen